Integration, Communication, Homeostasis Flashcards
Second messenger that binds Calcium channels of endoplasmic reticulum
Inositol triphosphate (IP3)
GPCR also uses lipid-derived 2nd messengers. Name the 3 messengers.
Phospholipase C
Diaglycerol (DAG)
Inositol triphosphate (IP3)
Name the important intracellular signal
Calcium
Calcium enters the cell via what kind of channels?
Gated channels
Short-acting paracrine/autocrine signaling molecule that acts close to where they are produced
Soluble Gases
Calcium binds to ___ or other regulatory proteins to trigger cell function
Calmodulin
Functions of nitric oxide
Vasodilator
Neurotransmitter/neuromodulator in the brain
Function of carbon monoxide
Activates GUANYLYL CYCLASE and targets SMOOTH muscle and neural tissue
Function of hydrogen sulfide
Targets cardiovascular system to relax blood vessels
Synthesis process of eicosanoids
Arachidonic acid cycle
Arachidonic acid is produced by the action of this enzyme
PLA2
How are leukotrienes produced? What is their role?
Produced via action of lipoxygenase on AA; role in asthma/anaphylaxis
How are prostanoids produced? What is their role?
Produced via action of COX on AA; prevent inflammation via inhibiting COX
The alpha isoform has a higher affinity for _______
Norepinephrine
The beta isoform has higher affinity for _____
Epinephrine
Blocks receptor entirely - no repsonse
Antagonist
Can activate a receptor but takes up binding site. Can still produce a response.
Agonist
Cell’s ability to respond to chemical signal is limited by # of receptors for that signal
Saturation
Decrease in # of receptors
(Cell can remove receptors via endocytosis)
Down Regulation
Target cells insert more receptors into the membrane
Up-regulation
Regulation is not “on” or “off” but is regularly mediated up or down
Tonic Control
What is antagonistic control and give example
How systems regulate and control opposing actions
Ex: parasympathetic and sympathetic NS
What happens to blood vessels under tonic control with decreased and increased signals?
Decreased - dilation
Increased - constricts
Compares input signal with setpoint
Integrating center
3 major components of reflex pathway
Input, Integrating Center, Output
Simple reflex system uses ___ OR ____ ; complex uses ___
Simple carried out by EITHER endocrine or nervous; complex uses both
The transmission of info from one side of a membrane to another using membrane proteins
Signal Transduction
The 2nd messenger is formed via intracellular molecules and can alter what 3 things?
Ion channels, calcium, enzyme activity
The extracellular signal is 1st messenger that activates what 2 things?
Protein kinases
Amplifier enzymes
List the order of basic signal transduction pathway
External signal
Receptor
Transducer
Amplifier
RESPONSE
Function of protein kinases
Transfer phosphate group from ATP to a protein
Function of amplifier enzymes
Activate intracellular 2nd messengers
Signal transduction pathways form a ____
Cascade
Ligand binding to receptor channels changes _____
Ion permeability
Most signal transduction uses what kind of proteins?
G proteins
Many lipophobic hormones use what kind of pathways for signal transduction?
GPCR - cAMP pathways
Chemicals released by NEURONs into the blood for action at distant targets
Neurohormones
The only means by which electrical signals can pass directly from cell to cell
Gap Junctions
Example of a paracrine signal
Histamine (released by damaged cells)
Peptides synthesized by all nucleated cells in response to stimulus (regulatory protein)
Cytokines
Which are made on demand and which are stored in advance in the endocrine cells?
Cytokines - on demand
Classic hormones - in advance
Membrane receptor where ligand binding opens an ion channel or alters enzyme activity
G protein - coupled
Membrane receptor in which ligand binding opens or closes the channel
Receptor-channel
4 methods of cell to cell communication
Gap junctions
Contact-dependent signals
Local communication
Long Distance communication
